The present invention relates to a novel cyclodextrin-silica composite and a method for the preparation of the same or, more particularly, to a composite, in which cyclodextrin moiety is incorporated into a matrix of amorphous silica, useful as a carrier of solid catalysts used in various chemical reactions, carrier of immobilized enzymes, microencapsulating agent of various kinds of chemical substances such as agricultural chemicals, insecticides, herbicides and photosensitive agents, filler in gel chromatography, absorbent or adsorbent, agent for material separation and purification and so on as well as a method for the preparation of such a composite.
Cyclodextrin is a recently highlighted chemical substance having a power of molecule clathration and catalytic activity and is widely used by utilizing these unique characteristics as a microencapsulating agent of various chemically unstable materials such as medicines, insecticides, herbicides and the like, solubilizing agent of some hardly soluble materials, filler in column chromatography and so on. More recently, attempts have been undertaken to modify or enhance the unique performance of cyclodextrins by introducing various functional groups into the chemical structure, by preparing a polymerized form of cyclodextrin and by preparing a composite of cyclodextrin with minerals with an object to utilize such a modified cyclodextrin as a carrier of an artificially immobilized enzyme products.
As is known, however, cyclodextrin has a chemical structure of a cyclized polysaccharide with a large number of hydroxy groups so that it is inherently not quite stable. Therefore, it is sometimes unavoidable that cyclodextrin is susceptible to structural changes by some reaction when it is used as a catalyst or encapsulating agent of artificial enzymes and photosensitive materials no longer to serve as a catalyst or encapsulating agent. In connection with the application as a filler in liquid chromatography, cyclodextrin cannot be used for the separation of materials in the form of an aqueous solution because cyclodextrin is readily dissolved in water. These disadvantages are the factors limiting the application fields of conventional cyclodextrin products.